Static electricity

Static electricity is a class of phenomena involving objects with a net charge; typically referring to charged objects with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks.

Generation

The presence of surface charge imbalance means that the objects will exhibit attractive or repulsive forces. This surface charge imbalance, which leads to static electricity, can be generated by touching two differing surfaces together and then separating them due to the phenomena of contact electrification and the triboelectric effect. Rubbing two non-conductive objects generates a great amount of static electricity. This is not just the result of friction; two non-conductive surfaces can become charged by just being placed one on top of the other. Since most surfaces have a rough texture, it take longer to achieve charging through contact than through rubbing. Rubbing objects together increases amount of adhesive contact between the two surfaces. Usually insulators, e.g., substances that do not conduct electricity, are good at both generating, and holding, a surface charge. Some examples of these substances are rubber, plastic, glass, and pith. Conductive objects only rarely generate charge imbalance except, for example, when a metal surface is impacted by solid or liquid nonconductors. The charge that is transferred during contact electrification is stored on the surface of each object. Static electric generators, devices which produce very high voltage at very low current (such as the Van de Graaf generator or Wimshurst machine) and used for classroom physics demonstrations, rely on this effect.

Related Topics:
Surface charge - Contact electrification - Triboelectric effect - Insulators - Rubber - Plastic - Glass - Pith - Conductive - Static electric generators - Van de Graaf generator - Wimshurst machine

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Note that the presence of electric current does not detract from the electrostatic forces nor from the sparking, from the corona discharge, or other phenomena. Both phenomena can exist simultaneously in the same system.

Related Topics:
Current - Corona discharge

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